This invention relates generally to package conveying method and apparatus, and more particularly to package conveying method and apparatus employing chain suspended trays for transporting cargo as between ship deck levels, or between floors of a building.
Present elevator systems, particularly those provided with tray chain suspension and control tracks for shipboard applications, frequently suffer from distortion, misalignment, and thus possible jamming. Distortion of the elevator casing or misalignment of upper or lower chain sprockets can prevent free movement of cargo trays carried by the chains of such elevator systems. Also, jamming is apt to occur at upper and lower levels when cargo trays carried by the chains change travel direction.
Examples of prior art elevator systems are U.S. Pat. No. 3,184,039 to Czarnecki; U.S. Pat. No. 1,461,638 to Wells et al; and U.S. Pat. No. 1,856,262 to Rebstock.